Water tank



FIG. 1 is a perspective view of a water tank, showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof;

FIG. 5 is a another side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

CLAIM We claim, the ornamental design for a water tank, as shown and described. 